In a PTN, protection on a user side and that on a network side are interlinked, and an Operation Administration and Maintenance-Mapping (OAM-Mapping) function is deployed on a user Attachment Circuit (AC) side to implement switching on the network side together in case of a failure on the user side. In order to isolate a user side failure from a network side failure, that is, when a user AC side fails, protection switching is only performed on the user side, and protection switching is not performed on the network side, so that influence on a service of the network side is further avoided. A manner adopted in a conventional art is implemented by a three-point bridge scenario deployed with a network side protection Multi-Chassis Pseudo Wire (MC-PW) and a user side Multi-Chassis Link Aggregation Group (MC-LAG) Dual Node Interconnection (DNI) Pseudo Wire (PW), that is, when a master service PW link fails, data on the network side is sent to an egress port of a master AC through a standby node, the DNI PW and a master node for continuous forwarding; and when the master AC fails, the data on the network side is sent to an egress port of a standby AC through the master node, the DNI PW and the standby node for continuous forwarding, so that the failure on the user side and the failure on the network side are separately protected without mutual interference.
However, when the master and standby ACs fail, the data on the network side which is forwarded by a head node Provider Edge (PE) is sent back to the head node PE through the master node, the DNI PW and the standby node, and when a double-receiving mode is configured for the head node, the self receiving and self sending of a data packet under a network structure occur, which may waste data traffic under the network structure.